1. Field
The present invention relates to a supercharger-equipped internal combustion engine to be mounted on a saddle-ride type vehicle on which a driver rides by straddling a seat, such as a saddle-ride type two-wheel vehicle, three-wheel vehicle or four-wheel vehicle (rough terrain vehicle) or a personal watercraft.
2. Description of the Related Art
To ride on a saddle-ride type vehicle, a driver straddles a seat. Having such form of a vehicle body, a saddle-ride type vehicle has a small limited space for installing devices including an internal combustion engine. For this reason, in a supercharger-equipped internal combustion engine in particular, it is not easy to secure a space for installing a supercharger as well as an intercooler which cools air compressed by the supercharger, and the like.
Heretofore, a personal watercraft has been disclosed as an example of a saddle-ride type vehicle on which a supercharger-equipped internal combustion engine is mounted.
The personal watercraft disclosed, for example, Japanese Patent Publication No. 2007-247518 (JP '518) has a body which is formed of a hull, and a deck covering the hull from above. At the center of the deck a little closer to the rear, a rectangular opening protruding upward is covered by a saddle seat long in a front-to-rear direction and narrow in a left-to-right direction.
In such a personal watercraft, a supercharger-equipped internal combustion engine is mounted on or in an engine room which is located under the seat and is surrounded by the hull and the deck.
In the supercharger-equipped internal combustion engine, an intake passage extends rearward of an internal combustion engine main body from a supercharger provided at the left lateral side of the internal combustion engine main body, and is connected to an intercooler provided behind the internal combustion engine main body. Moreover, another intake passage extends from the intercooler toward the right lateral side of the internal combustion engine main body, and is connected through a throttle body to an intake manifold provided in a protruding manner at the right side of a cylinder head.
As described above, the supercharger-equipped internal combustion engine disclosed in JP '518 has such a structure that the supercharger is provided to protrude toward the left side of the internal combustion engine main body, that the intake manifold extends toward the right side of the internal combustion engine main body, and that the throttle body is placed behind the intake manifold. Due to such a structure, the internal combustion engine is large in a body-width direction, and therefore the sheet size of the saddle seat covering the internal combustion engine from above is also wide in the left-to-right direction. For this reason, a driver has to sit down with his/her legs wide apart.
It is desired to reduce the size, in a width direction, of a vehicle such as a motorcycle and a rough terrain buggy. Thus, it is difficult to employ the layout as disclosed in the example of JP '518.
Embodiments of the present invention have been made in view of the above points, and has an object to provide a supercharger-equipped internal combustion engine for a saddle-ride type vehicle formed in such a small size in a width direction of a vehicle body as to be accommodated in a space of a saddle sheet of the saddle-ride type vehicle, the space being narrow in a left-to-right direction.